Abstract:
Plectranthus amboinicus is knowns us traditional plant medicine in dif erent rural and
urban community. However, production and usage of this traditional medicines require a
scientific techniques and supports for the appropriate development of antibacterial drugs. The current study was intended to investigate phytochemical screening and antibacterial
activities of Plectranthus amboinicus crude extracts, against pathogenic bacteria using the
disc dif usion method. The minimum inhibitory concentrations of the extracts were
assessed using broth dilution method. Amoxicillin and sterilized distilled water were used
as positive and negative controls, respectively in the determination of antimicrobial
activities. The results of qualitative analysis of the crude extracts revealed the presence of
alkaloids, tannins, saponins, anthraquinones, flavonoids, terpenoids, and steroids. Phlobatannin has been found absent in both stem and leaf examined. With regard to the
antibacterial activities of the crude extracts, ethanol crude extracts of leaf and stem
showed better antibacterial activities than the crude extracts obtained using water solvents. The ethanol leaf extract showed 15.62, 15.21, 14.36 and 14.21mm of the zone of inhibitions
against S. aureus, S. pyogenes, S. Typhi and E. coli, respectively, at a concentration of 150
mg/ml. The result shows four tested bacterial species S. aureus and E. coli were the most
and least susceptible, respectively. Data was analysed by SPSS, version 27. The inhibitory
ef ects of the crude extracts were significantly dif erent at p<0.05. The MIC of the crude
extracts was generally in the range of 25.00 to 100.00mg /ml against the four tested
bacterial species However, the minimum bactericidal concentrations values ranged from
50 to 125mg/ml against the four tested bacterial species. In general, the present
investigation shown that the leaf and stem extracts of P. amboinicus have antimicrobial
potential for selected pathogen. However, further research is needed for isolation and
quantification of the specific bioactive compounds to authenticate the most important
chemical component
